Many ocular diseases occur in highly specific geometries, in particular along the vertical and horizontal axes of the eye. The purpose of this proposal is to determine whether or not these geometries result from a hidden ocular map, wherein broad ocular areas of seemingly identical histological appearance have submicroscopic and point-to-point map-like differences with properties peculiar to the vertical and horizontal axes, a Cartesian coordinate system in which ordinate and abscissa dictate the relative positions of various structures within the eye. The nature of this map will be explored by utilizing a variety of embryonic experiments. It is the principal investigator's contention that there are two adhesive (or chemotactic) gradients, one across the vertical axis and a less steep one across the horizontal axis of the eye. These gradients could enable displaced cells to regain their original positions; cells could migrate more easily across the vertical axis than across the horizontal axis. Cellar migration will be assessed by using chick-to-quail ocular transplants. These species contain different nuclear markers that can be followed with development. If the embryonic and disease maps are related, this might provide a new insight into the etiologies of a variety of ocular diseases, including the degenerations and dystrophies which present in characteristic patterns.